The present disclosure relates to solar roof tiles. More particularly, it relates to photovoltaic module assemblies including a removably mountable wind deflector.
Solar power has long been viewed as an important alternative energy source. To this end, substantial efforts and investments have been made to develop and improve upon solar energy collection technology. Of particular interest are industrial- or commercial-type applications in which relatively significant amounts of solar energy can be collected and utilized in supplementing or satisfying power needs.
Solar photovoltaic technology is generally viewed as an optimal approach for large scale solar energy collection, and can be used as a primary and/or secondary (or supplemental) energy source. In general terms, solar photovoltaic systems (or simply “photovoltaic systems”) employ solar panels made of silicon or other materials (e.g., III-V cells such as GaAs) to convert sunlight into electricity. More particularly, photovoltaic systems typically include a plurality of photovoltaic (PV) modules (or “solar tiles”) interconnected with wiring to one or more appropriate electrical components (e.g., switches, inverters, junction boxes, etc.). The PV module conventionally consists of a PV laminate or panel generally forming an assembly of crystalline or amorphous semiconductor devices electrically interconnected and encapsulated. One or more electrical conductors are carried by the PV laminate through which the solar-generated current is conducted.
Regardless of an exact construction of the PV laminate, most PV applications entail placing an array of PV modules at the installation site in a location where sunlight is readily present. This is especially true for commercial or industrial applications in which a relatively large number of PV modules are desirable for generating substantial amounts of energy, with the rooftop of the commercial building providing a convenient surface at which the PV modules can be placed. As a point of reference, many commercial buildings have large, flat roofs that are inherently conducive to placement of a PV module array, and is the most efficient use of existing space. While rooftop installation is thus highly viable, certain environment constraints must be addressed. For example, the PV laminate is generally flat or planar; thus, if simply “laid” on an otherwise flat rooftop, the PV laminate may not be optimally positioned/oriented to collect a maximum amount of sunlight throughout the day. Instead, it is desirable to tilt the PV laminate at a slight angle relative to the rooftop (i.e., toward the southern sky for northern hemisphere installations, or toward the northern sky for southern hemisphere installations). Further, possible PV module displacement due to wind gusts must be accounted for, especially where the PV laminate is tilted relative to the rooftop as described above.
To address the above concerns, conventional PV module array installation techniques have included physically interconnecting each individual PV module of the array directly with, or into, the existing rooftop structure. For example, some PV module configurations have included multiple frame members that are physically attached to the rooftop via bolts driven through (or penetrating) the rooftop. While this technique may provide a more rigid attachment of the PV module, it is a time-consuming process and permanently damages the rooftop. Also, because holes are formed into the rooftop, distinct opportunities for water damage arise. More recently, PV module configurations have been devised for commercial, flat rooftop installation sites in which the arrayed PV modules are self-maintained relative to the rooftop in a non-penetrating manner. More particularly, the PV modules are interconnected to one another via a series of separate, auxiliary components. One or more wind-deflecting barriers (or “wind deflectors”) are assembled to some or all of the PV modules to reduce (or deflect) a magnitude of wind forces imparted upon an underside of the PV module and/or array. Ballast may also be provided.
In light of the above, wind deflectors are important to the success of an installed, non-penetrating PV module array. One conventional PV module configuration permanently affixes the wind deflector(s) as part of the PV module and/or the mounting system used to interconnect adjacent PV modules in the array. The fixed wind deflector design can make installation and connection of the PV module array wiring highly difficult, and is characterized by substantial packaging and shipping costs. Conversely, other conventional PV module designs employ wind deflectors that are movable or removable relative to the PV module frame, and are installed thereto via bolts or other threaded fasteners. The corresponding installation process is labor-intensive, and can be a potential source of quality problems.
Regardless of the PV module/wind deflector format, the wind deflector(s) is typically arranged at an angle or sloped relative to the corresponding PV laminate (i.e., the wind deflector is non-perpendicular relative to the PV laminate) to optimize performance. At the northern edge of the PV array (for northern hemisphere installations), wind loads are typically at their highest and the wind deflector is beneficially arranged at a shallow slope. While existing PV module/wind deflector configurations may facilitate this desired sloped positioning, it is not possible to “select” a different wind deflector orientation. As a result, when two of the so-configured PV modules are connected to one another as part of an array, the shallow sloped wind deflector occupies a significant portion of the space between the PV modules, significantly impeding access for installation and maintenance. Even further, for a given wind deflector tilt angle, there is an ideal spacing (ground coverage ratio) that strikes a good balance between maximum output from the entire array and minimum losses from shading of one row by a neighboring row. Where the PV module/wind deflector allows for only a single wind deflector title angle, the ground coverage ratio of the corresponding array is essentially fixed, but many times may not be optional for a particular installation site.
In light of the above, any improvements in the construction of PV modules/wind deflectors for non-penetrating installation will be well-received.